Corsaire Security Advisory - VMware ESX Server Cross Site Scripting issue

– Corsaire Security Advisory –

Title: VMware ESX Server Cross Site Scripting issue
Date: 14.11.05
Application: VMware ESX prior to 2.5.2 upgrade patch 2
VMware ESX prior to 2.1.2 upgrade patch 6
VMware ESX prior to 2.0.1 upgrade patch 6
Environment: VMware ESX
Author: Stephen de Vries [[email protected]]
Audience: General distribution
Reference: c051114-002

– Scope –

The aim of this document is to clearly define an issue that exists with
the VMware ESX Server product [1] that will allow a remote attacker to
inject arbitrary active scripting content, such as JavaScript, into a
web session.

– History –

Discovered: 11.11.05 (Stephen de Vries)
Vendor notified via client: 15.11.05
Vendor notified directly: 19.05.06
Document released: 01.06.06

– Overview –

VMware ESX Server is described [1] as virtual infrastructure software
for partitioning, consolidating and managing servers in mission-critical
environments.

The software provides a virtualization layer that allows multiple x86
based operating systems to run on the same hardware concurrently. The
ESX Server product differs from other VMware products in that it does
not require a "host" operating system to be provided by the user.
Instead, it uses a custom x86 kernel as the host, along with a
customised Linux operating system as a "console O/S".

VMware ESX Server includes a number of network services and a web
application, called the "VMware Management Interface" that can be used
to perform remote administration of the system.

– Analysis –

The VMware ESX Server product provides a web application to perform
management of the system. One of the functions of this application is
to allow administrative users to view log files, such as syslog, through
a browser. No encoding of syslog data is performed to ensure that HTML
meta-characters are not interpreted by the browser. This allows an
attacker to inject HTML content, including JavaScript, into the syslog
file where it would be rendered or executed when viewed through the
Management Interface. Since the raw syslog data is displayed between
<div> tags, it is necessary to close the tag for a clean injection. Two
injection methods were detected:

1. An attacker could simply attempt to log in to the Management
   Interface with a username that contains the injection script, such as:

</div><script>alert('XSS')</script>

2. An attacker could attempt to log in to the ftp server with a
   username containing a similar injection string.

It should be noted that the ftp server is not enabled by default,
however, the Management Interface is.

This flaw could be used to conduct any number of Cross Site Scripting
attacks [2], such as Session Hijacking, Cross Site Request Forgery or
apparent falsification of the syslog data.

The risk of this vulnerability is increased due to the fact that only
administrative users have permission to view the syslog files through
the Management Interface. Should a Session Hijacking attack be
successful, it would therefore likely yield administrative access.

– Recommendations –

Upgrade to a version of the VMware ESX product that does not exhibit
this issue:

VMware ESX 2.5.2 upgrade patch 2 and later
VMware ESX 2.1.2 upgrade patch 6 and later
VMware ESX 2.0.1 upgrade patch 6 and later

– CVE –

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2005-3619 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardises names for
security problems.

– References –

[1] http://www.vmware.com/products/esx/
[2] http://www.aspectsecurity.com/topten/xss.html

– Revision –

a. Initial release.
b. Minor edits.
c. Released.

– Distribution –

The information contained within this advisory is supplied "as-is" with
no warranties or guarantees of fitness of use or otherwise. Corsaire
accepts no responsibility for any damage caused by the use or misuse of
this information.

– Disclaimer –

The information contained within this advisory is supplied "as-is" with
no warranties or guarantees of fitness of use or otherwise. Corsaire
accepts no responsibility for any damage caused by the use or misuse of
this information.

– About Corsaire –

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in Guildford, Surrey, UK. Corsaire bring innovation, integrity and
analytical rigour to every job, which means fast and dramatic security
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